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Title: Reflectance and Resolution of Multilayer Monochromators for Photon Energies from 400 - 6000 eV

Abstract

This paper deals with multilayer monochromators for synchrotron beamlines that are produced by magnetron and ion beam sputter deposition (MSD and IBSD). Different material combinations (W/B4C, W/Si, Mo/B4C, Mo/Si) with period thicknesses between 1 nm and 10 nm have been fabricated and measured at the synchrotron BESSY II (optics and KMC1 beamlines). The main challenge for the deposition of nanometer multilayers is to find growth conditions where the interfaces between adjacent layers are abrupt (no interdiffusion {sigma}d) and smooth (no roughness {sigma}r). The interface width {sigma} ({sigma}{sup 2} = {sigma}{sub d}{sup 2} + {sigma}{sub r}{sup 2}) becomes increasingly important for smaller period thicknesses. One decisive point for the interface formation is the kinetic energy distribution of the particles arriving on the substrate surface. In MSD, the sputter gas pressure is the main parameter for influencing the kinetic energy of the particles. In IBSD, an assist ion beam source can be used to bombard the growing film with inert gas atoms of a specific energy. Using this option, the best compromise between low interdiffusion and low roughness can be found for every material combination. Investigations of the reflection of W/B4C multilayers with period thicknesses of 1.2 nm and number of periodsmore » N = 50, 300 and 600 show that no roughness increase occurs with increasing N. Typical values for the interface widths are {sigma} = 0.27...0.28 nm.« less

Authors:
; ; ;  [1]; ;  [2]
  1. IWS Dresden, Fraunhofer-Institut fuer Werkstoff- und Strahltechnik, Winterbergstr. 28, 01277 Dresden (Germany)
  2. Berliner Elektronenspeicherring-Gesellschaft fuer Synchrotronstrahlung m.b.H (BESSY), Albert-Einstein-Str. 15, 14489 Berlin (Germany)
Publication Date:
OSTI Identifier:
21052561
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 879; Journal Issue: 1; Conference: 9. international conference on synchrotron radiation instrumentation, Daegu (Korea, Republic of), 28 May - 2 Jun 2006; Other Information: DOI: 10.1063/1.2436106; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; BEAM OPTICS; BESSY STORAGE RING; DISTRIBUTION; INTERFACES; ION BEAMS; LAYERS; MONOCHROMATORS; PHOTON BEAMS; PHOTONS; REFLECTION; REFLECTIVITY; RESOLUTION; ROUGHNESS; SPUTTERING; SUBSTRATES; SURFACE COATING; SURFACES; SYNCHROTRON RADIATION; THICKNESS

Citation Formats

Braun, Stefan, Gawlitza, Peter, Menzel, Maik, Leson, Andreas, Mertin, Marcel, and Schaefers, Franz. Reflectance and Resolution of Multilayer Monochromators for Photon Energies from 400 - 6000 eV. United States: N. p., 2007. Web. doi:10.1063/1.2436106.
Braun, Stefan, Gawlitza, Peter, Menzel, Maik, Leson, Andreas, Mertin, Marcel, & Schaefers, Franz. Reflectance and Resolution of Multilayer Monochromators for Photon Energies from 400 - 6000 eV. United States. doi:10.1063/1.2436106.
Braun, Stefan, Gawlitza, Peter, Menzel, Maik, Leson, Andreas, Mertin, Marcel, and Schaefers, Franz. Fri . "Reflectance and Resolution of Multilayer Monochromators for Photon Energies from 400 - 6000 eV". United States. doi:10.1063/1.2436106.
@article{osti_21052561,
title = {Reflectance and Resolution of Multilayer Monochromators for Photon Energies from 400 - 6000 eV},
author = {Braun, Stefan and Gawlitza, Peter and Menzel, Maik and Leson, Andreas and Mertin, Marcel and Schaefers, Franz},
abstractNote = {This paper deals with multilayer monochromators for synchrotron beamlines that are produced by magnetron and ion beam sputter deposition (MSD and IBSD). Different material combinations (W/B4C, W/Si, Mo/B4C, Mo/Si) with period thicknesses between 1 nm and 10 nm have been fabricated and measured at the synchrotron BESSY II (optics and KMC1 beamlines). The main challenge for the deposition of nanometer multilayers is to find growth conditions where the interfaces between adjacent layers are abrupt (no interdiffusion {sigma}d) and smooth (no roughness {sigma}r). The interface width {sigma} ({sigma}{sup 2} = {sigma}{sub d}{sup 2} + {sigma}{sub r}{sup 2}) becomes increasingly important for smaller period thicknesses. One decisive point for the interface formation is the kinetic energy distribution of the particles arriving on the substrate surface. In MSD, the sputter gas pressure is the main parameter for influencing the kinetic energy of the particles. In IBSD, an assist ion beam source can be used to bombard the growing film with inert gas atoms of a specific energy. Using this option, the best compromise between low interdiffusion and low roughness can be found for every material combination. Investigations of the reflection of W/B4C multilayers with period thicknesses of 1.2 nm and number of periods N = 50, 300 and 600 show that no roughness increase occurs with increasing N. Typical values for the interface widths are {sigma} = 0.27...0.28 nm.},
doi = {10.1063/1.2436106},
journal = {AIP Conference Proceedings},
number = 1,
volume = 879,
place = {United States},
year = {Fri Jan 19 00:00:00 EST 2007},
month = {Fri Jan 19 00:00:00 EST 2007}
}
  • Measurements of the reflectrance R for V/sub 2/O/sub 5/ single crystals and photon energies h..omega.. from 2 eV to 14 eV are given, and the spectral dependence of the real and imaginary parts of the dielectric constant epsilon and of the refractive index N is calculated for h..omega..< or =7 eV. A discussion of the results obtained is given; and according to it, the optical properties of V/sub 2/O/sub 5/ for 2.2 eV< or =h..omega.. < or =8eV or 9 eV are connected chiefly with 2p (O/sup -2/) ..-->..3d (V/sup +5/) electronic transitions and for h..omega..>8 eV or 9 eVmore » with transitions between the 2p (O/sup -2/) and 4s (V/sup +5/) electronic states. It is shown that the dispersion of epsilon for h..omega.. below the intrinsic absorption edge is chiefly determined by strong optical transitions near 3 eV, and the absorption edge in this material corresponds to the low energy tail of a weak absorption band with a maximum at 2.5 eV. An investigation of the shape of the R (h..omega..) extrema of V/sub 2/O/sub 5/ single crystals is carried out, and a comparison of these characteristics with the analogous dependencies for other oxides of transition metals (SrTiO/sub 3/ and NiO) as well as with the transmission spectra of dilute solutions of V/sub 2/O/sub 5/ is made. On the basis of such an investigation a hypothesis is given about the significant contribution that localized excitations together with interband transitions, make to the optical properties of this material. (AIP)« less
  • The reflectance spectra of Co- and Nb-doped BaTiO/sub 3/ crystals have been measured for photon energies from 1.8 to 70 eV. For both types of crystal, structures observed in the 1.8 to 2.3 eV range can be attributed to the presence of residual impurities. Between 2.3 and 3.2 eV the peaks in the reflectance of the Co-doped crystal are found to be of an acceptor charge transfer type. For Nb-doped crystals structures appear at the bottom of the conduction band. For energies larger than 3.2 eV the spectra are characteristic of pure BaTiO/sub 3/ crystals, in reasonable agreement with thosemore » determined by Baeuerle et al. and calculated by Michel-Calendini and Moretti. 15 refs., 4 figs., 1 tab.« less
  • Examinations were made of 15 electron-photon showers with energies from 10/sup 11/ to l0/sup 13/ ev recorded in emulsion stacks. Energies of primary quanta causing showers were determined by measuring the energy spectrum of cascade electrons at a depth of 2.5 to 3 rad units, and by the screening effect on the first pairs. The energy spectrum was measured of pairs, produced at a depth of 1.5 rad units. The results obtained agree with the calculations made taking into account the influence of multiple scattering and medium polarization on high energy electron bremsstrahlung. (auth)
  • Neutron transmission through a zirconium oxide sample containing the radioactive /sup 93/Zr isotope was measured by pulsed neutron time of flight. R matrix parameters for some of the resonances up to 6-keV neutron energy were determined. The first resonance, for example, was found at (110.43 +- 0.01) eV with partial widths GAMMA/sub N/ = (348 +- 9) meV and GAMMA..gamma.. = (141 +- 21) MeV and quantum numbers J..pi.. = 2/sup +/.
  • We investigated experimentally the charge exchange of He/sup +/, Ne/sup +/, and Ar/sup +/ in internal excited states 4d/sup 9/5s/sup 2/ /sup 2/D/sub 3///sub 2/,/sub 5///sub 2/ of Cd II and 3d/sup 9/4s/sup 2/ /sup 2/D/sub 3///sub 2/ of Zn II in the energy interval 2--400 eV. It is established that the interacting particle pairs are characterized, at appreciable energy defects of approx. 7eV, by high energy-transfer efficiency (approx. 10/sup -16/ cm/sup 2/) and their charge-exchange cross sections exhibit a qualitatively different behavior at low energies. Calculation shows that the charge exchange makes a noticeable contribution to the population ofmore » the upper laser levels for lambda=4415 A He--Cd lasers and lambda=5894 A He--Zn lasers. (AIP)« less